The physical components of a finished corrugated container or box consist of two types of paperboard, which together are called containerboard. The two types of containerboard are linerboard and corrugated medium. Both types of containerboard are manufactured at paperboard mills out of either recycled pulp or virgin pulp. Because of an increased desire to include recycled pulp in a finished product many manufacturers of virgin pulp containerboards include a portion of recycled pulp in the furnish. Typically, linerboard and corrugated medium are made at different facilities, however, it is also common for linerboard and corrugated medium to be made at the same facility on different machines.
Because of differing desired specifications for pulp furnish for linerboard and corrugated medium, they are not made from the same pulping process. The differences are more striking in this regard with virgin pulp processes, where pulp for linerboard is made from a sulfate process and pulp from corrugated medium is made from a Neutral Sulfite green liquor or carbonate Semi-Chemical Process. These differences greatly contributed to the reason that the majority of manufacturing of linerboard and corrugated medium are done in separate facilities. With an increasing emphasis on recycling, the majority of new linerboard and corrugated medium production facilities are made with 100 percent recycled pulping processes.
Due to economics of scale considerations, as the industry grew, so did the size of its paper machines. For example, larger machines meant, among other things, lower labor costs. Board machines since the 1960's have been in the 300+ inch web width at speeds in excess of 3,000 feet per minute, with machines producing over 2,000 tons per day. These mills were built near forest resources, primarily in the southeast.
Due to a push for recycling content to be in all paper and board products, mills began to recycle by repulping Old Corrugated Containers (OCC). This OCC pulp typically is 20% to 40% of the total furnish, with existing virgin kraft pulp as the balance. This shift in production, changed the transportation logistics of the process. More specifically, OCC had to travel from the urban end user area back to the mills at the forest who in turn would ship the finished product back to the urban end user. In other words, the recycled fiber content on average made a 1,500 mile round trip. The prior art process incurs a tremendous freight charge.
Another transportation problem associated with the prior art mills is that the normal or natural market for sales from a corrugated plant is best described as being within a radius of 100 to 200 miles. The reason for this relatively small radius is that corrugated products are very bulky to transport and the price of the products is very low. This means that transportation as a percentage of the sales, price is very high. Compounding this is that containerboard is typically supplied to converting plants from locations that probably average 750 miles from the corrugated box plant by rail or by truck. This is outside of the normal or natural market and therefore affords no backhaul potential to defray the high outbound transportation from a corrugated box plant.
Scrap packaging is generated by nearly 100% of the companies that use corrugated containers. For example, nearly every manufacturer buys materials in corrugated containers and in turn ships it's outbound products in corrugated containers. Unfortunately, the amount of scrap generated at a typical location is inadequate to warrant the investment in a heavy duty baler that could impact sufficient density to the scrap material to allow it to be economically shipped hundreds of miles back to the containerboard mill for recycling. Similarly, retail outlets must either have high density balers or must collect lighter material which is sold to packers that prepare high density bales to ship to paper mills.
Virgin board mills are faced with increasing environmental compliance costs due to changing standards applied to the environmentally complex pulping system. Recycled mills, on the other hand, have been moving toward improved processes that minimize and even eliminate effluent discharge and have relatively minimum particulate and odor air emissions compared to their virgin mill conterparts. This allowed for these mills to be placed in urban settings.
Since these urban mills could be targeted for a smaller market (the urban area in which they serve) and automation has reduced labor needs for the process, these mills have been able to over come the economy of scale considerations and be competitive with the large virgin mills. The mills have been called mini-mills. Typically they are in the range of 400-700 tons per day with machines in the 160 to 250 inch web width range, operating at speeds that are less than 1/2 that of the fastest machines. These narrow widths and slower speeds have reduced the complexity of the machines, and therefore, the cost.
Despite these changes the mini-mills operate in the same fashion as the virgin mills they grew out of. The mills produce board as an intermediate product, to be shipped to corrugators, who use the rolls, to manufacure corrugated sheets. These sheets in turn are either made into boxes at the plant (this essentially involves printing, die cutting, folding and gluing) or are sold to sheet plants that convert the sheets to finished boxes for customers. These corrugators and box makers can either be part of the same company as the board manufacturer or are outside customers of the mill.
While this product flow and the necessary manufacturing steps to accomplish this flow had made sense for the virgin board manufacturer in the past, it involves many wasteful and unneeded steps associated with the recycled board manufacturing industry. Yet, due to the legacy of virgin board manufacturing, all mini-mills continue to pursue the product flow and all the unnecessary steps.
Since prior art board machines are much larger than even the largest corrugator, all parent rolls coming off the board machine must be slit and rewound on a rewinder. This adds to capital cost. A rewinder costs over $1,000,000. There is also a significant labor cost (up to 5% of the labor for board manufacture) in the rewinding process.
In the prior art there is a considerable wastage of trim (i.e., clippings and other wastage problems). Further, in the prior art, the width of the board machines is not matched to industry corrugators. Plus, prior art mills serve numerous clients with different width requirements due to differing corrugator widths. This results in trim rolls that sit on a warehouse floor for long periods of time. These trim rolls are sold most of the time at prices well below the mill's costs. Accordingly, waste of unusable trim is an economic problem.
Another economic factor involving trim is that in the prior art it must be shipped back to the mills to be recycled. Mills ship board to corrugator and box makers. Waste (trim, i.e., clippings and other wastage) from corrugator and box making must in turn be shipped back to the mill for recycling.
The present invention comprises Integrated Packaging, which is directed to an improved system and process of manufacturing corrugated sheets, corrugated containers and other paper board products. The benefit of Integrated Packaging is: lower project capital costs, lower manufacturing costs, lower overhead costs, which results in greater opportunities for manufacturing in urban areas, lower packaging costs, less damaging environmental practices through fewer processing steps and lower transportation needs of producing the ultimate final product (which yields lower transportation vehicle emissions).